Use identities to find the exact value.
24) cos(-75°)

( - )

Step-by-step explanation:

Using the addition formula for cosine

cos(x - y) = cosxcosy + sinxsiny

and the exact values

sin45° = cos45° =

cos60° = , sin60° =

Note that

cos(- 75)° = cos(45 - 120)°, thus

cos(45 - 120)°

= cos45° cos120° + sin45° sin120°

= cos45° ( - cos60°) + sin45° sin60°

= × - + ×

= - +

= ×

=

= ( )

6.9

step-by-step explanation:

simple math really

6 1/2 times 0.6 = 3.9

but if you are just doing 6 and not 6 1/2 then the answer is 3.6